Canon Cat Reference Manual page 96

Sorting From Large to Small
You can reverse the usual order of sorting by uslng
[SH:FTl－
[SORT].Numbers win be sorted from large to
small;alphabeticd listings will be in reverse dphabetica
order(Z to A).(To uSe[sH:FTI-lSORTl,preSS and hold
[uSE FRONTl and[SHIFT],anC Whne hOlding both keys,
press and release[soRT].)
UNDO andtheSORT Command
Asortjustcompletedcanbelmsorted.[UNDO]retums the
records to their original unsorted order.